Jeep Grand Cherokee Start Stall Idle Problems

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Hey all..got a 1994 JGC 5.2..last year at this time my Jeep would not start and you could hear the relay clicking...my local dealership determined that it was an O2 sensor and that they were getting no response from the ECM. I bought a used ECM and replaced it and the Jeep worked fine..until the summer when it started to just stall..it would sputter and I would have to rev it to keep it going...then it would sometimes rev itself and thge RPM's would shoot all over..now what's happening is my voltage meter is dropping whenever I use anything (lights, heat etc) and the sputtering is back in full force..but the last two things only happen when the Jeep is warmed up. Sometimes it starts back up..other times it will not fire and the only way to get it to run is to unhook the ECM and re-hook it back up..then it starts right up...oh one last thing..when my central monitor reads 10000km to service, the Jeep sputters and shuts off..happened THREE times in a row and once I reset it, it works fine. But oddly my km's to service reset to 12068km's..what's that all about? HELP ME BOYS!!!

You're absolutely right - DC / Jeep takes enormous pride in trying to out-Lucas the 'Prince of Darkness' with electrical gremlins. Fortunately most are more easily remedied than your old Brit-mobile.

Connectors get oxidized & throw off the ECU sensor voltages. Cleaning them with contact cleaner (non-solvent base!) & putting a little dielectric grease in them can often work wonders. Sometimes a ground jumper wire around a bad connector is enough to fix a particular issue - depends on the circuit affected.

For the Jeeps made since AMC got out of the game - ground cables are known issues. Just expect it to cause problems one day so go ahead now and spend less than $5 to replace the braided factory one from the engine to the firewall with a generic battery ground cable w/ eye terminals on each end.

While I focus on Jeep XJ's with the older RENIX based engines, I'll gladly help anyone I can or at least point you in the correct direction for help. You can contact me in this thread or on my email form at my website:

finally i have others with my same problem. i have a 1996 JGC, 4.0 and have the flickering dash lights, doors only lock and unlocking on occasion, jumping idle at stops and when cold, stalling when at stops, all very random and increasing in occurence. i have replaced the feul pump last year, also the ignition coil, IAC, and just replaced cap, rotor, plugs and plug wires, as i knew i needed those done. still same problem. my next step is going to be the fuel filter again, and possibly the throttle position sensor. any other ideas? other than this mystery, i love my jeep. also, should i disconnect the battery in order for the computer to find the new IAC?

Check your ground cable from the engine to the firewall + from the battery. Everything you describe isn't just random, nor (we hope...) is your Jeep possessed! Common to all these things is the electrical system and bad ground cables are VERY common - especially the braided garbage cable from the engine to the firewall.

There is also a electrical feed plug on the firewall than can, on occassion, give problems. It's low on the list of suspects but the vast majority of electrical connections to the interior run though it.

If you have a straight drive - make sure there hasn't been any leakage of fluid from the clutch master cylinder down the inside beneath your dash onto the fuse panel, or any electrical connectors. It's nothing more than brake fluid and eats up many plastics & paint.

Yes, please post back! It's a cheap fix of a common item that causes a LOT of wierd behavior on these vehicles. Should cost under $5.00 at AutoZone etc... It will eliminate that engine ground strap as a potential cause & we can go from there.

No worries - Open the hood.Look on the firewall near the engine on the driver-side. There should be a flat, braided steel cable bolted there that runs from that point over to the rear of the engine's head.

If that's gone then you should see the bolt hole there, perhaps with the bolt still there. (Metric size, I think.) You can just run the new cable from that point and bolt it to the back of the engine or head. (Not on the manifold or valve cover bolts - those are not good ground points either.)

I think I have a schematic on my site of the engine bay. Let me check & I'll repost.

i looked and i don't see a braided steel cable anywhere. and many of my cables and wires are covered in those black plastic covers. hmm. i wish i could find it, as i am so curious about this. let me know if you find the schematic of the engine bay.

Yes, I have the schematic. Wasn't posted on my site but I'm editing the files right now. My XJ isn't here or I would just shoot a photo & post it for ya... I'll do that as an edit for the article I'm getting ready to post to my site in a few days but the schematic should help you find it.

On older 4.0L's the ground cable wasn't braided - it was just part of the engine harness but went to the same locations. Sorry, I thought you had a newer XJ (the forum format here isn't the greatest & I simply didn't pick up on it.)

Just to double check - post your model, year & engine size... but here's what to look for on a 4.0L engine:

Look on your engine's dipstick tube. (Holds the dipstick that you use to check oil.) It's bolted to the passenger side of the block. The bolt that holds it in place to the block should have a wire grounded to it. THAT is the engine end where the OEM harness connection on my 1990 XJ goes to the block. Make sure your new cable is long enough to go from there to the firewall bolt.

To begin: Engine end:You can bolt your new cable to the dipstick tube bolt, or any other available bolt - but for simplicity - let's assume you choose that one.

Just remove the nut, pull off the existing ground wire, scuff up the area a bit with a wire brush if you'd like, install one end of your new cable there, reinstall the OEM ground wire, replace the nut & tighten. (Don't overdo it but get it tight.)

Firewall end:Standing in front of your Jeep, facing the windshield... Look for a bolt on the firewall, about 8" to the right of center and near the upper side of the firewall. It should be a black wire with a metal connector on the end being held down by a bolt. Once you see it, just remove that bolt. The OEM ground wire will likely come off with it - no problem. Just remove the OEM ground wire and SCUFF THE WIRE's CONNECTION METAL with a wire brush or sandpaper. Install your new ground cable beneath the OEM ground wire and reinstall the bolt.

I'll have those diagrams up in a few minutes for you and post the URL here.

my jeep is a 1996 Grand Cherokee Laredo, 6cl, 4.0, 2WD. if that helps at all. i will take a look again shortly and look for that ground cable.again, thanks so much for being here and your willingness to help out. i have been at my wits end with this problem for so long......fingers crossed!

Glad to help! Just hoping that this is the source of your problems - the symptoms fit but I've been wrong before. Either way - under $5 & you help eliminate this as a cause.

Forgot to mention but I highlighted the areas to look for in yellow on the diagrams.

Your Grand Cherokee's engine is a newer version of the one in my standard XJ model Cherokee but we can treat it the same for this problem.

Grand Cherokees I've seen do have that ground strap as described but if your engine has been pulled / replaced / serviced in the past it may have been removed and not reinstalled... Or I may be all wet and yours will have the same standard black insulated wire as mine!

Either way - this ground wire causes so many erratic issues that drive people nuts it isn't funny. Should have been a factory recall item for correction.

ok, so i found where the oil dipstick tube is bolted to the side of the engine. but the wire that leads from there does NOT go to the firewall. i found that large bolt on the firewall just to the right of center, but nothing is connected to it. it extends out pretty far, and has a rubber tip on the end. sorry to be such an amateur, but i am a bit confused. but those diagrams really helped. i will ask my husband to take a look too when he gets home. perhaps i am just not seeing something.

Ok - you can still use that dipstick bolt & run the cable from there to that bolt on the firewall with nothing connected to it. The grounds that connect to the dipstick tube/motor must be left connected - they are harness grounds, but you can just add the new cable right to the same point if you'd like.

Evidently, your OEM ground strap has been removed when the engine was worked on. It may even be hanging down behind the motor and still connected to the harness so do a quick check for that. (I've also seen them just ripped off and left hanging torn by mechanics who think the motor mounts will ground the motor properly. NOT! )

HTH

Feel free to access my mail form on my website and email me directly - I can give you guys my Yahoo name & I can walk you through it online. A link to mail me is on every tech page.

ok, so we just installed the generic cable with the eye ends, one end to the oil dipstick tube, it had 2 wires already connected to it that run from there through the top right side of the engine. so we took those 2 off and placed one end of our new cable on, then placed those 2 on top, and tightened all 3 onto the ground there at the oil dipstick. then we ran that new cable and connected it to the bolt/ground at the center dash/firewall. you said this bolt should be about 8" from the center toward the drivers side, but this one is almost directly dead center. i also see another one on the passengers side with nothing connected to it.anyway, the cable is now connected to the engine/oil dipstick mount/ground and to the bolt sticking out from the dash. and i started it up and it still seems a bit rough and idle unstable. but we will see about the stalling tomorrow. if so, i will be asking what next...you mentioned another cable running to the battery before?

Thanks for the heads up on CarSpace - actually I hide it deliberately to help reduce spam. My email form is through a third party mailer so my email address is never "out there" / visible unless I reply. Doesn't stop the spam problem but does extend the time between address changes.

I don't have a Grand Cherokee FSM ( factory service manual ) so I cannot verify the firewall ground point in the center... It may be there BUT when I personally helped someone with a Grand fix this I recall the cable ran to the driver side of the firewall. (Again - that Grand had a factory installed flat, braided ground strap.)

Is there a threaded hole in the location I described?

Or an empty one nearby that looks like it may had a bolt in it at one time?

If you used a bolt that had a painted area beneath it - you should ensure that there is good metal to metal contact. (We don't want to sand off all the paint... only a small area DIRECTLY beneath the cable terminal)

What about your gages & other erratic behavior? Was there any change in the other symptoms?

(Idle issues with these engines area also common - usually vacuum leaks etc...)

Has it thrown any codes / check engine light staying on? (You can get a free code scan at your local AutoZone.)

nothing that looked like it had a bolt at one time, just the one barely right of center on the firewall and one over by the passenger side. should i try that one? i am also going to try scraping/sanding more of the paint around the bolt too, see if that helps. i have noticed that i no longer get a tiny shock when i get out and close the the door. BUT, i just ran an errand and it cut out and died on me twice, but started right back up again. when it started to die, the rpm's get really bouncy and low, it sputters, and no matter how much to step on the gas, it doesn't help or respond, then it goes dead.no check engine light, no codes, as usual.so i will try scraping the connection a bit more, it was dark last night when we did this and probably didn't do a great job.by the way, i don't have any vaccum leaks at all. so we can rule that out.what about the battery cables and ground?

Ok - check that you have a good ground & we'll continue along from there...

Any sign of a braided ground strap hanging loose behind the engine? (I've seen them ripped clean to the connector - may just be a fuzzy stub under a bolt.)

Any erratic gage behavior?

Any erratic lighting - interior, dash, etc. acting weird?

When it misbehaves - are the headlights etc fully functional & bright?

Yes, check your battery cables ESPECIALLY if you have some of those aftermarket battery terminals from AutoZone, etc... They often get oxidized/corroded & can cause some weirdness that mimics other problems. I've also seen them come new with paint over-spray on the cable contact area!... they need to be cleaned with a wirebrush & then the cables re-clamped. (Best option is to replace those things with new factory style cables from a local parts store.)The aftermarket battery terminal/clamps I'm referring to are generic ones that have two bolts on top of them that clamp onto the original battery cable in cases where it pulled loose, or came out of the original clamp. Factory ones will only have the single bolt running into the side of the clamp and when tightened grips the battery terminal post... _OR_ with side post batteries there will be a single bolt that goes through the center of the cable terminal and screws directly into the battery's terminal.

While you have your terminals loose - leave the battery disconnected, turn the key "ON", then to start, then back off. Pause a few seconds each time. This should clear any stored codes and reset the computer to 're-learn' the motor.

(( On my own Jeep - I ran an additional ground cable from the battery negative to the same ground point at the dipstick you just used. Keep in mind that I have my Jeep set up for hi-current accessories (winch, etc) so this is overkill IF your cables are good and you don't have a hi-watt stereo etc.) ))

How did you rule out vacuum leaks? 4.0L engines can get them along the intake manifold due to loose manifold bolts / studs. (Heat / cool cycle over time loosens the bolts & studs holding the manifolds to the engine.) You can check for vacuum leaks along the manifold with an old windex bottle filled with water, or a can of starting fluid with a nozzle to direct the spray along the manifold. Water will seal up a leak momentarily & change the engine revs (should smooth out...) and the starting fluid will make the engine rev higher momentarily if there is a leak. (Try to avoid letting fumes enter the airbox or it'll give misleading results.)

Do you have a digital volt meter? Intermittent stalls can be caused by a faulty Crankshaft Position Sensor (CPS) though I would think it "should" throw a code on your Grand's computer.

Ok - check that you have a good ground & we'll continue along from there...

Any sign of a braided ground strap hanging loose behind the engine? (I've seen them ripped clean to the connector - may just be a fuzzy stub under a bolt.)

Any change in the other behavior?

Any erratic gage behavior?

Any erratic lighting - interior, dash, etc. acting weird?

When it misbehaves - are the headlights etc fully functional & bright?

Yes, check your battery cables ESPECIALLY if you have some of those aftermarket battery terminals from AutoZone, etc... They often get oxidized/corroded & can cause some weirdness that mimics other problems. I've also seen them come new with paint over-spray on the cable contact area!... they need to be cleaned with a wirebrush & then the cables re-clamped. (Best option is to replace those things with new factory style cables from a local parts store.)The aftermarket battery terminal/clamps I'm referring to are generic ones that have two bolts on top of them that clamp onto the original battery cable in cases where it pulled loose, or came out of the original clamp. Factory ones will only have the single bolt running into the side of the clamp and when tightened grips the battery terminal post... _OR_ with side post batteries there will be a single bolt that goes through the center of the cable terminal and screws directly into the battery's terminal.

While you have your terminals disconnected - leave the battery disconnected, turn the key "ON", then to start, then back off. Pause a few seconds each time. This should clear any stored codes and reset the computer to 're-learn' the motor. There may be a specific method to do this for your Grand in your owner's manual.

(( On my own Jeep - I ran an additional ground cable from the battery negative to the same ground point at the dipstick you just used. Keep in mind that I have my Jeep set up for hi-current accessories (winch, etc) so this is overkill IF your cables are good and you don't have a hi-watt stereo etc.) ))

How did you rule out vacuum leaks? 4.0L engines can get them along the intake manifold due to loose manifold bolts / studs. (Heat / cool cycle over time loosens the bolts & studs holding the manifolds to the engine.) You can check for vacuum leaks along the manifold with an old windex bottle filled with water, or a can of starting fluid with a nozzle to direct the spray along the manifold. Water will seal up a leak momentarily & change the engine revs (should smooth out...) and the starting fluid will make the engine rev higher momentarily if there is a leak. (Try to avoid letting fumes enter the airbox or it'll give misleading results.)

Do you have a digital volt meter?

The "usual suspect" in stalling / quitting followed by intermittent no-starts is a faulty Crankshaft Position Sensor (CPS) though I would think it "should" throw a code on your Grand's computer. If you have a meter, we can check that easily enough.

We'll run through that & if we can't figure it out I'll give you a URL for a Grand Cherokee web-forum. You can search their threads & ask some guys (& gals) who'd sleep with their Jeep if it would fit through the bedroom door and their spouse would let it inside. (Yes, Jeepers can be an obsessive lot...)

Engine off, vehicle in Park. Rock the Jeep forward and backward a couple of times. Get in and try to start it. Sometimes the Park/Lock cable gets a bit stretched and doesn't allow the lock to be turned forward. Rocking the car relieves tension on the cable and on the Park/Lock function on the ignition switch.

Since lunghd has all the answers... i need help too!!I have a 99 JGC, V8. It has been stalling out when it runs on idle in park for more than 5 mins, and it will stall when driving down the road, (At any speed), and while stopped at a stop light. NO issues with lights dimming and what not though.we have noticed that when it shuts off randomly, all the gauges are... gauging things, if you will, EXCEPT the fuel gage. and everytime we try to start it after a stall, the fuel gauge continues to stay on E, until it finally decides to start... before we monkey around with other things you've suggested, do you think its a fuel pump or filter problem?? or SOMETHING do to with the fuel stuff?

Did you ever have this problem? Noone seems to know how to fix this issue with my Jeep. The car starts and I'm driving an suddenly it just shuts off. Steering,everything! Then I try to restart the Jeep and it starts up, but when I take my foot off the gas it shuts off again. I spent a large amount of money on the matter and it still is the same. The gas station gave me a new battery, It was not the problem, and they replaced the speed sensor twice because it was burned. Now they said it might be a computer problem RPM? Does anyone have any advise for me? I'm so worried to drive this Jeep again. I almost got killed with these sudden brakedowns. The mechanic said just drive it and if it happens again tow it back to him. It will happen again and I'm running out of $. Please, adives thanks

Hah - wish I did have all the answers. I have a 4.0L 6 cylinder & that's my primary focus however your symptoms do mimic a failing CPS (crankshaft position sensor) on a 4.0L. I unfortunately have NO idea where that is located on the chrysler engine your grand has & don't have a Factory Service Manual for a grand here.

Yes, it could be a fuel problem... or other things.

Does it stall out "gradually" or just quit immediately? Does it immediately restart, crank for a long time & then immediately restart?Or crank for a long time then sputter & spit then restart?Or do you have to let it sit for a while before it'll start?

I'll give it a try but let me also refer you to the grand cherokee forum on JeepsUnlimited.com where you can do a search through existing posts / threads for this and if you can't find a good result... you can post the question there for the Grand Cherokee specialists.